This invention relates to a composition and method of manufacturing urea-based synthetic urine. More specifically, the synthetic urine includes biocides to allow for increased shelf stability.
An example of a method of manufacturing synthetic urine may be seen by reference to U.S. Pat. No. 7,192,776, the disclosure of which is hereby incorporated by reference in its entirety.
The kidneys remove unwanted substances circulating in the blood by way of producing urine, which is excreted from the body. Consequently, diverse waste substances and other substances unwanted by the body find their way into urine for subsequent removal from the body. Urinalysis is the testing of the composition and amounts of waste substances in urine, and provides a tremendously powerful diagnostic tool for the medical profession. In particular, many of these substances are indicative of certain medical conditions or other substances which have been metabolized by a person's kidneys.
Using current urinalysis techniques, unwanted substances in a urine sample can mask existing medical conditions, while still some others can masquerade as non-existent medical conditions. In each instance, these unwanted substances undermine the usefulness of urinalysis as a medical diagnostic tool. Some of the unwanted substances that find their way into a urine sample are drugs (both legal and illegal) and metabolites thereof, along with other chemical residues or contaminants that may be present or otherwise contacted during the handling procedures. These substances can disturb the sensitive tests, making the actual state of the body difficult or impossible to determine.
For example, urea compounds, uric acid, insulin levels, para-aminohippuric acid, phenol sulfonphthalein, phosphate, arylsulfatase-A, lysosome, urine amylase, total urine estrogens, specific estrogens, progestins, aldosterone, catecholamines, 5-hydroxyindoleacetic acid, cortisol, homovanillic acid, human chorionic gonadotrophin, creatine, bilirubin, hemoglobin, hydroxyproline, melanin, porphorins, total protein, acid mucopolysaccharide, copper, glucose oxidase and urine ketone can all influence the results of most standard urinalysis testing methods in unintended or unpredictable ways.
Essentially, these testing methods include a variety of immunoassays or assays by other techniques, such as isolation followed by gas or liquid chromatography followed by mass spectrometry. These tests make urinalysis a powerful diagnostic tool for identifying a whole range of conditions. For example, substance abuse and other indicia of disease or bodily state can easily be detected by urinalysis. However, in order to accurately establish standards of comparison for such tests, reliable urine samples are needed which are entirely free from any of the aforementioned substances. Thus, the development of a suitable, synthetic urine substitute would improve testing methods by providing researchers, potential urine donors and testing technicians with an accurate baseline reading for “clean” urine samples to compare against other suspect samples.
To illustrate, a method for detecting this compound is described in U.S. Pat. No. 5,036,014, issued to Elsohly et al., where various deuterated cannabinoids are synthesized to help determine the quantitative amount of tetrahydrocannabinol in a urine sample. One method in particular involves spiking a clean urine sample with known amount of deuterated tetrahydrocannabinol and analyzing the resultant sample with gas chromatography/mass spectrometry in order to establish set standards of comparison. However, a failure to possess a truly clean sample could substantially influence and negatively affect the results of these methods.
Another example of the problems created by interfering chemicals in urine is exemplified by the case of ibuprofen. Ibuprofen is a prostaglandin synthetase inhibitor that may be taken in large doses to relive pain and inflammation characteristic of arthritis. When a patient taking these massive doses is subjected to urinalysis, it may mask other drugs being taken by the donor, or may even be mistaken for tetrahydrocannabinol (a metabolite which many testing technicians classify as being indicative of marijuana use).
Any misidentification of controlled substance use/abuse, personal information (pregnancy, use of cigarettes, etc.) or any of the numerous medical conditions that can be determined using urinalysis can have devastating personal consequences for the urine donor. Thus, some companies sell inexpensive home testing kits in order to provide some level or reassurance to potential urine donors whether they may have such a misidentification. However, given the potential liability for a misidentified or positive test, many lay persons feel intimidated by testing procedures, and these persons would welcome the ability to utilize a known sample, free from unwanted or unknown substances, for the sake of comparison.
In response to the need for a reliable source of relatively inexpensive, “clean” urine samples which are free from any unwanted or unknown substances, numerous attempts to formulate synthetic urine have been made. For example, U.S. Pat. No. 6,306,422 to Batich et al. (table 3, col. 16, line 50 et seq.), U.S. Pat. No. 5,328,954 to Sarangapani (table 1, col. 9, line 29 et seq.), U.S. Pat. No. 5,489,281 to Watanabe et al. (col. 12, example 6) and U.S. Pat. No. 4,146,644 to Griffith et al. (table 1, col. 10). However, none of these references appears to address a simple composition which can be manufactured in an inexpensive manner that contains urea or can be supplemented with urea, and has shelf-stability from use of biocides.
Additionally, all of these references require the use of creatinine or other compounds which can be consumed by bacteria present in the sample. Accordingly, all of these samples will undergo sepsis unless they are immediately used, thereby making these compounds unattractive candidates for mass production and/or consumer sales.